1. Field of the Invention
This invention relates in general to a packaged semiconductor and specifically to a coating for the leads of the packaged semiconductor.
2. Description of the Related Art
Leaded packaged semiconductors typically include leads made of metal materials such as copper alloys or metal alloys. One problem with these packaged semiconductors is that the lead material may oxidize prior to a packaged semiconductor's attachment to a circuit board.
Prior methods for preventing oxidation have included coating the leads with metals such as, e.g., tin-lead, nickel-palladium, nickel-palladium gold, tin, and other tin alloys. Besides adding extra weight and expense, these metals may have a propensity to form “whiskers” after their application. Whiskers are spontaneously formed single crystal filaments of the coating material. These whiskers may cause shorts in circuits implementing the packaged semiconductor.
What is needed is a technique for reducing the problems of oxidation of the leads yet which does not produce the above identified problems associated with the conventional coatings.